1. Field of the Invention
This invention relates to article conveyors and, more particularly, to conveyors with movable pushers for diverting articles away from a principal conveying direction.
2. Background Art
A conventional conveyor construction employs article carrying tubes that are arranged in pairs for movement in an endless path. It is known to cause the conveyed articles to travel in other than the principal conveying direction as the conveyor operates.
In Turnbough (U.S. Pat. No. 4,319,676), articles from multiple feeding conveyors are converged toward a single discharge conveyor. To accomplish this end, pushers are mounted movably relative to the tube pairs, guided by tracks in predetermined paths transversely to the principal conveying direction as the tubes advance and engage and divert the moving articles.
The pushers in Turnbough comprise cooperating members that are bolted together around the tubes for sliding movement lengthwise relative to the tubes. If the cooperating pusher members are drawn too tightly against the tubes, the pushers bind and might jam the entire conveyor. If the pusher members are too loose in relationship to the tubes, unwanted play occurs.
There is also a tendency of the tubes in each pair in Turnbough to skew relative to each other as the conveyor operates. If this occurs, movement of the pusher members lengthwise of the tubes might be impaired.
It is a further drawback with the Turnbough structure that the upper pusher members are guided directly against the upper surfaces of the tubes. The upper surfaces of the tubes are directly contacted by the articles during conveyance and may therefore be subject to wear. This may adversely affect the ability of the upper pusher members to slide freely over the tube surfaces. Liquid spill on the tubes can make the upper tube surfaces sticky and might also impair sliding of the pushers.
A further problem with prior art systems is that structure used to move the article carrying tubes often resides outside the extremities of the tubes. For example, it is conventional to have a drive chain outside the ends of the carrying tubes. As the articles are directed laterally off of the principal conveyor, they may encounter interference from the chain. Repeated contact with the chain by the articles might damage the chain or cause accumulation of foreign matter that might impair its operation.
A further problem with prior art structures such as Turnbough's is that the guide tracks are discontinuous resulting in the pushers being unsupported as they travel the curved path about the conveyor end supports. The unsupported pushers tend to rattle.